Replace!

When you save a file and get the "Replace existing <filename>?" dialog, this extension will make the Replace button, rather than the Cancel button, be the default. Requires System 7 or later. Will not slow down your Mac. Freeware.

On PowerPC systems running Mac OS 8.5 or later, some applications use a different style of dialog, which Replace! can also modify, as shown below. Version 1.1.1 fixes a bug in this case: the Replace button looked like the default, but pressing Return still activated the Cancel button.